Marketing authorisation for rare diseases: The European regulatory perspective using the example of gene and cell therapies

Technological and scientific innovations in the area of gene and cell therapies, so-called advanced therapy medicinal products (ATMPs), have contributed to the steep increase in treatment options for patients with rare diseases. They offer opportunities to address the underlying genetic defect by gene addition, i.e., the delivery of the gene of interest to the target cells, or by genome editing approaches through direct repair of disease-causing mutations. This paper outlines clinical evidence requirements in the context of marketing authorisations for rare diseases. Two out of fifteen gene therapies that have been approved in the European Union since 2018 are used as case studies: Libmeldy (atidarsagen autotemcel) for the treatment of patients with metachromatic leukodystrophy, and Roctavian (valoctocogen roxaparvovec) for the treatment of patients with haemophilia A. Special aspects of the evaluation of single-arm trials with small sample size and requirements with regard to the isolation and causal attribution of the treatment effect are discussed. The role of clinical data obtained under everyday conditions (real world data) to support the generation of evidence in the pre- and post authorisation phase is critically examined. Furthermore, the paper outlines aspects related to conditional versus standard marketing authorisations as well as aspects related to registry-based non-interventional studies in the context of market and patient access to urgently needed drugs.